# GO-2026-6225: Credential leakage to untrusted hosts in github.com/chrismellard/docker-credential-acr-env

> An attacker can steal Azure AD access tokens by registering a malicious hostname containing .azurecr.io, exploiting an unanchored regex in the credential helper.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Aug 2026

## What is GO-2026-6225?

GO-2026-6225 is a vulnerability in github.com/chrismellard/docker-credential-acr-env, published on 18 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In github.com/chrismellard/docker-credential-acr-env/pkg/credhelper, the regular expression used by isACRRegistry to validate Azure Container Registry hostnames is unanchored. As a result, arbitrary hostnames containing the substring ".azurecr.io" (such as evil.azurecr.io.attacker.com) are treated as valid ACR registries, causing ACRCredHelper.Get to send the Azure Active Directory (AAD) access token to attacker-controlled hosts.

## Which versions are affected by GO-2026-6225?

1 open source package ship an affected version, including github.com/chrismellard/docker-credential-acr-env.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/chrismellard/docker-credential-acr-env` | Go | All versions | None |

## How do I fix GO-2026-6225?

No fix has been published for GO-2026-6225 yet. Limit exposure of the affected software until one is available.

## Is GO-2026-6225 being exploited?

There is no known exploitation of GO-2026-6225 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GO-2026-6225 and fix it if it is affected.

What it is: GO-2026-6225 is a vulnerability in github.com/chrismellard/docker-credential-acr-env, published on 18 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GO-2026-6225 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/chrismellard/docker-credential-acr-env (Go): affected all versions; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GO-2026-6225/ (Markdown: https://insights.sbomify.com/GO-2026-6225/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GO-2026-6225

---
From sbomify Insights: https://insights.sbomify.com/GO-2026-6225/
Summaries are generated and may contain mistakes; the official description above is the record.